U.S. patent application number 10/749639 was filed with the patent office on 2004-11-04 for body frame of vehicle, employing load imposing device.
This patent application is currently assigned to HONDA MOTOR CO., LTD.. Invention is credited to Mae, Hiroyuki.
Application Number | 20040217627 10/749639 |
Document ID | / |
Family ID | 32501184 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040217627 |
Kind Code |
A1 |
Mae, Hiroyuki |
November 4, 2004 |
Body frame of vehicle, employing load imposing device
Abstract
A body frame of a vehicle for securing, in control of buckling,
necessary strength without increasing the size of the frame member,
and for reducing impact deceleration produced at the start of
buckling. The body frame of has a frame member provided in one of a
front portion and a rear portion of the vehicle; and a load
imposing device, provided at an end of the frame member, for
imposing a load on the frame member toward at least two opposite
directions which are substantially perpendicular to a longitudinal
direction of the frame member, when impact on the frame member is
anticipated or imposed. The load imposing device may have a member
made of a shape memory alloy.
Inventors: |
Mae, Hiroyuki; (Shioya-gun,
JP) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
HONDA MOTOR CO., LTD.
Tokyo
JP
|
Family ID: |
32501184 |
Appl. No.: |
10/749639 |
Filed: |
December 31, 2003 |
Current U.S.
Class: |
296/187.03 |
Current CPC
Class: |
B62D 21/15 20130101 |
Class at
Publication: |
296/187.03 |
International
Class: |
B62D 025/08 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 7, 2003 |
JP |
2003-001136 |
Claims
What is claimed is:
1. A body frame of a vehicle, comprising: a frame member provided
in one of a front portion and a rear portion of the vehicle; and a
load imposing device, provided at an end of the frame member, for
imposing a load on the frame member toward at least two opposite
directions which are substantially perpendicular to a longitudinal
direction of the frame member, when impact on the frame member is
anticipated or imposed.
2. A body frame as claimed in claim 1, wherein the load imposing
device has a member made of a shape memory alloy.
3. A body frame as claimed in claim 1, wherein the load imposing
device has a spring.
4. A body frame as claimed in claim 3, wherein the spring is one of
a coil spring and a plate spring.
5. A body frame as claimed in claim 1, wherein the load imposing
device has a band-shaped member made of a shape memory alloy, which
is wound along one of an outer-peripheral wall and an
inner-peripheral wall of the frame member.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a body frame for vehicles.
Priority is claimed on Japanese Patent Application No. 2003-001136,
filed Jan. 7, 2003, the content of which is incorporated herein by
reference.
[0003] 2. Description of the Related Art
[0004] In a known vehicle body structure, concave portions called
"beads" are provided at an end portion of the front frame, so that
when a compressive load is imposed on the front frame, buckling of
the front frame is controlled in a manner such that the front frame
buckles from the concave portions (refer to Japanese Unexamined
Patent Application, First Publication No. Hei 07-165110).
[0005] In the above known structure, the strength of the frame
member itself is decreased due to the concave portions; thus, the
size of the frame member should be increased so as to secure
necessary strength, thereby increasing the weight of the vehicle.
Additionally, in such a passive control in which concave portions
are provided at the frame member, impact deceleration produced at
the start of buckling is increased. In other words, high impact
deceleration is produced even in a low-speed crash.
SUMMARY OF THE INVENTION
[0006] In consideration of the above circumstances, an object of
the present invention is to provide a body frame of a vehicle for
securing, in control of buckling, necessary strength without
increasing the size of the frame member, and for reducing impact
deceleration produced at the start of buckling.
[0007] Therefore, the present invention provides a body frame of a
vehicle, comprising:
[0008] a frame member (e.g., a front side frame 12 in an embodiment
explained below) provided in one of a front portion and a rear
portion of the vehicle; and
[0009] a load imposing device (e.g., a load imposing device 13 in
the embodiment), provided at an end of the frame member, for
imposing a load on the frame member toward at least two opposite
directions which are substantially perpendicular to a longitudinal
direction of the frame member, when impact on the frame member is
anticipated or imposed.
[0010] According to the above structure, the buckling of the frame
member is controlled by imposing a load by the load imposing device
on the frame member toward at least two opposite directions which
are substantially perpendicular to a longitudinal direction of the
frame member, when impact on the frame member is anticipated or
imposed. Therefore, it is unnecessary to provide concave portions
at the frame member. Accordingly, in control of the buckling,
necessary strength of the frame member can be secured without
increasing the size of the frame member, and impact deceleration
produced at the start of buckling can be reduced.
[0011] As a typical example, the load imposing device has a member
(e.g., a spring 25 in the embodiment) made of a shape memory alloy.
In this case, the load imposing device imposes a load on the frame
member by using a member made of a shape memory alloy, so that the
load imposed state can be continued for a desired time, thereby
easily controlling the operation timing of the load imposing
device.
[0012] The load imposing device may have a spring. In this case,
the spring is one of a coil spring and a plate spring.
[0013] The load imposing device may have a band-shaped member made
of a shape memory alloy, which is wound along one of an
outer-peripheral wall and an inner-peripheral wall of the frame
member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a perspective view showing the body frame of a
vehicle, as an embodiment according to the present invention.
[0015] FIG. 2 is a perspective view showing the load imposing
device used in the body frame in the embodiment.
[0016] FIG. 3 is a graph showing (i) the characteristics (see the
solid line) of the buckling load (along the vertical axis) versus
the displacement (along the horizontal axis) for the body frame of
the embodiment of the present invention, and (ii) the corresponding
characteristics (see the dashed line) of a body frame which has no
load imposing device.
[0017] FIG. 4 is a graph showing (i) the characteristics (see the
solid line) of the impact deceleration (along the vertical axis)
versus the displacement (along the horizontal axis) for the body
frame of the embodiment of the present invention, and (ii) the
corresponding characteristics (see the dashed line) of a body frame
which has no load imposing device.
[0018] FIG. 5 is a perspective view showing a variation of the load
imposing device used in the body frame in the embodiment.
[0019] FIG. 6 is a perspective view showing a variation of the body
frame in the embodiment.
[0020] FIG. 7 is a diagram including a sectional view of the main
structural portion of another variation of the body frame in the
embodiment.
[0021] FIG. 8 is a side view of the pressing member in the load
imposing device of the body frame shown in FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Hereinafter, the body frame of a vehicle, as an embodiment
according to the present invention, will be explained with
reference to the drawings.
[0023] As shown in FIG. 1, the body frame 11 of the present
embodiment has a front side frame 12 (i.e., a frame member) and a
load imposing device 13. The front side frame 12 is a framework
member of the vehicle, which is provided at a front portion of the
vehicle (body) and in the front-back direction of the vehicle. The
load imposing device 13 is provided at the front end of the front
side frame 12, that is, the front end in the front-back direction
of the vehicle. When an impact on the front side frame 12 is
anticipated or received, the load imposing device 13 imposes a load
on the front side frame 12 toward at least two opposite directions
which are substantially perpendicular to the longitudinal direction
of the front side frame 12. In addition, an extension (not shown)
is attached to the front end of the front side frame 12, that is,
the front end in the front-back direction of the vehicle, where the
extension deforms prior to deformation of the front side frame 12
when receiving impact.
[0024] The front side frame 12, made of steel or the like, is
formed by joining a frame forming member 15 having a U-shaped cross
section and a frame forming member 16 having a plate shape, in a
manner such that the frame forming members 15 and 16 form a closed
section. The load imposing device 13 is provided at the front end
(in the front-back direction of the vehicle) and inside the front
side frame 12 and is arranged in the right-left direction of the
vehicle.
[0025] More specifically, the frame forming member 15 has (i) a
side plate portion 18 formed along the vertical direction and also
the front-back direction of the vehicle, (ii) an upper plate
portion 19 and a lower plate portion 20, which respectively extend,
in the right-left direction of the vehicle, from the upper and
lower edges of the side plate portion 18, and which are arranged in
parallel to each other along the front-back direction of the
vehicle, and (iii) an upper flange 21 and a lower flange 22, which
respectively extend from the upper plate portion 19 and the lower
plate portion 20 in the vertical direction in a manner such that
the flanges 21 and 22 extend away from each other, where the upper
flange 21 and the lower flange 22 extend from sides (of the plate
portions 19 and 20) opposite from the sides which join the side
plate portion 18. The upper flange 21 and the lower flange 22 are
joined to the plate-shaped frame forming member 16. Both ends of
the load imposing device 13 are respectively joined to the side
plate portion 18 (of the flame forming member 15) and the frame
forming member 16 which are in parallel to each other.
[0026] As shown in FIG. 2, the load imposing device 13 includes (i)
a spring (member) 25 which is made of a shape memory alloy and is
coiled, (ii) a pair of contact members 26 and 27, which are
attached to both ends of the spring 25, (iii) an electric heater
28, provided inside the spring 25, for heating the spring 25, and
(iv) a power source (not shown) for supplying power to the electric
heater 28. As shown in FIG. 1, in this load imposing device 13, the
pair of contact members 26 and 27 are fastened to both side walls
(in the right-left direction of the vehicle) of the front side
frame 12, that is, to the frame forming member 16 and the side
plate portion 18 of the frame forming member 15 by welding or the
like, so as to hold the load imposing device 13 inside the front
side frame 12.
[0027] In the load imposing device 13, while the spring 25 is not
heated by the electric heater 28, the spring 25 does not stretch
and no load is imposed on the front side frame 12. Conversely, when
the spring 25 is heated by the electric heater 28, the spring 25,
made of a shape memory alloy, extends and stretches so that a load
is imposed on the front side frame 12 toward two opposite
directions along a right-left direction which is substantially
perpendicular to the longitudinal direction of the front side frame
12.
[0028] In the body frame 11 (of the vehicle) having the
above-explained load imposing device 13 in the present embodiment,
when a crash into an object in front of the vehicle is anticipated
by radar sensing for detecting such a forward object, or when a
crash happens and impact due to the crash is detected (i.e., when
impact is imposed), a part of the impact energy, which cannot be
absorbed by deformation of the extension, is absorbed by buckling
of the front side frame 12. Here, in the load imposing device 13,
the spring 25 is heated and lengthened by the electric heater 28.
Accordingly, a load is imposed to the front side frame 12 toward
two directions (in a right-left direction) which are perpendicular
to the direction of the compressive load which is imposed on the
front side frame 12 along the longitudinal direction of the front
side frame 12, thereby controlling the buckling of the front side
frame 12.
[0029] That is, the buckling of the front side frame 12 is
controlled by imposing a load on the front side frame 12 toward two
opposite directions in the right-left direction; thus, it is
unnecessary to provide concave portions at the front side frame 12.
Therefore, in control of the buckling, necessary strength of the
front side frame 12 can be secured without increasing the size of
the front side frame 12, and impact deceleration produced at the
start of buckling can be reduced. Here, the spring 25, made of a
shape memory alloy, may be made extend and contract by performing
heating control of the electric heater 28.
[0030] More specifically, in the front side frame 12 having the
load imposing device 13, as shown by the solid line in FIG. 3 (in
which "DISPLACEMENT" indicates displacement due to buckling), both
the buckling load (i.e., minimum compressive load for inducing
buckling) and the gradient of the load can be reduced at the start
of buckling, in comparison with a front side frame which does not
employ the load imposing device, indicated by the dashed line in
FIG. 3. In addition, as shown by the solid line in FIG. 4 (in which
"DISPLACEMENT" indicates displacement due to buckling), the impact
deceleration produced at the start of buckling can be reduced in
comparison with a front side frame which does not employ the load
imposing device, indicated by the dashed line in FIG. 4.
[0031] For example, in a low-speed crash in which a crash of the
vehicle into a forward object at a low speed is detected using
radar sensing, when a load is imposed on the front side frame 12
toward two opposite directions along a right-left direction (of the
front side frame 12) by heating the spring 25, made of a shape
memory alloy, via the electric heater 28 and by stretching the
spring 25, buckling is accelerated and the buckling load is
reduced, thereby reducing the impact deceleration. As a result, it
is possible to prevent an erroneous action of the airbag in a
low-speed crash.
[0032] On the other hand, in a high-speed crash in which a crash of
the vehicle into a forward object at a high speed is detected using
radar sensing, if no heating using the electric heater 28 is
executed in the load imposing device 13 and thus no load is imposed
on the front side frame 12, then buckling is not accelerated and
the buckling load is increased, thereby increasing the impact
deceleration. As a result, it is possible to quickly deploy the
airbag in a high-speed crash.
[0033] If a hole 29 (for a jig or the like) is provided in the
front side frame 12, as shown in FIG. 1, then conventionally,
breakage occurs in the front side frame 12 from such a hole 29 when
a crash happens. However, when employing the load imposing device
13, the buckling is mainly produced around the front end of the
frame. Therefore, it is possible to prevent the stress from being
concentrated around the hole 29, and the buckling of the front side
frame 12 can be controlled so as to start the buckling from the
front end.
[0034] The above-explained body frame 11 of the vehicle may be
modified as explained below.
[0035] As shown in FIG. 5, instead of providing the electric heater
28 inside the spring 25 of the load imposing device 13, power may
be directly supplied to the spring 25, made of a shape memory
alloy, by using a power source (not shown), so as to stretch the
spring 25. According to this structure, the spring can be quickly
stretched, thereby improving the responsiveness. Here, the spring
25 may be suitably heated so as to make the spring 25 (made of a
shape memory alloy) contract and extend.
[0036] Instead of the load imposing device 13, a load imposing
device 130 as shown in FIG. 6 may be employed. The load imposing
device 130 has (i) a band 30 (i.e., a band-shaped member) which is
made of a shape memory alloy and is wound around the front side
frame 12 (see FIG. 6), (ii) an electric heater (not shown) which
may be provided inside the front side frame 12, and (iii) a power
source (not shown) for supplying power to the electric heater. In
this structure, heating using the electric heater is performed so
as to impose a load in a manner such that the front side frame 12
is tightened up by the band 30 from all directions in the vertical
and right-left directions. Here, the band 30 may be wound along the
inner-peripheral wall of the front side frame 12 so as to impose
force for expanding the front side frame 12 from the inside of the
frame.
[0037] In another variation, instead of using the spring 25 of the
load imposing device 13, increase in the air pressure due to
gunpowder ignition may be used for forcing the pair of contact
members 26 and 27 towards the opposite directions. However,
according to the structure using a shape memory alloy in the load
imposing device 13 (so as to impose a load on the front side frame
12), the load imposed state can be continued for a desired time,
thereby easily controlling the operation timing of the load
imposing device 13. Therefore, a structure using a shape memory
alloy is preferable.
[0038] In addition, instead of the spring, a rod (member) made of a
shape memory alloy may be used.
[0039] Furthermore, a plate spring may be used instead of the
coil-shaped spring 25. That is, instead of the load imposing device
13, a load imposing device 1300 as shown in FIG. 7 may be employed.
In the load imposing device 1300, a fastening member 33 is fixed at
the center of a cylinder-shaped or square-shaped pipe member 32,
and plate springs 34 and 34 are provided at both sides of the
fastening member 33 in the pipe member 32. In addition, pressing
members 35 and 35 are respectively provided outside the plate
springs 34 and 34.
[0040] Here, the pressing member 35 has a structure as shown in
FIG. 8, in which the pressing member 35 has a disk shape. In FIG.
8, a protruding portion 36 is formed at the center of the pressing
member 35, and each pressing member 35 is arranged in the pipe
member 32 in a manner such that the protruding portion 36 is
present at the opposite side to the corresponding plate springs 34
(i.e., the protruding portion 36 does not face or contact the plate
springs 34).
[0041] At both opening ends of the pipe member 32, flanges 37 and
37 are respectively formed. In the load imposing device 1300, the
flanges 37 and 37 are fastened to both side walls (in the
right-left direction) of the front side frame 12, that is, to the
frame forming member 16 and the side plate portion 18 of the frame
forming member 15, by welding, using bolts, or the like.
[0042] In this load imposing device 1300, power is directly
supplied to the plate springs 34 and 34, which are made of a shape
memory alloy, by using the power source 38 (see FIG. 7) so as to
heat the plate springs 34 and 34. The power source 38 includes (i)
a photo MOS relay 39 connected to the plate springs 34 and 34, (ii)
electric cells 40 and 41, and (iii) a switch 42. While the switch
42 is off and the plate springs 34 and 34 are not heated by the
power source 38, the plate springs 34 and 34 do not expand so that
no load is imposed on the front side frame 12. Conversely, when the
switch 42 is turned on and the plate springs 34 and 34 are heated
by the power source 38, each plate spring 34, made of a shape
memory alloy, expands towards the directions indicated by the
double-headed arrow X in FIG. 7. Accordingly, the plate springs 34
and 34 are stretched so that a load is imposed, via the protruding
portions 36 of the pressing members 35, on the front side frame 12
towards two opposite directions (in the right-left direction)
substantially perpendicular to the longitudinal direction of the
front side frame 12.
[0043] When the plate springs 34 and 34 are used as explained
above, a larger load can be produced by using a spring member
having a smaller size, in comparison with a coil spring. Therefore,
the amount of shape memory alloy used can be reduced, and thus an
actuator having a high output and a low price can be realized.
[0044] Instead of providing the load imposing device (13, 130, or
1300) at the front end of the front side frame 12, the load
imposing device may be provided at the rear end of a rear frame
which is also a framework member (of the vehicle body) along the
front-back direction of the vehicle and which is provided at a rear
portion of the vehicle. In this case, effects similar to those
obtained by the structure in which the load imposing device 13 is
provided at the front end of the front side frame 12 can also be
obtained.
[0045] While preferred embodiments of the invention have been
described and illustrated above, it should be understood that these
are exemplary of the invention and are not to be considered as
limiting. Additions, omissions, substitutions, and other
modifications can be made without departing from the spirit or
scope of the present invention. Accordingly, the invention is not
to be considered as being limited by the foregoing description, and
is only limited by the scope of the appended claims.
* * * * *